I had this same issue and after about 3 months I found it. The headliner has little foam spacing blocks in it that have double sides tape on them. Once they wear out they will click or tap because they are not sticky enough. Here is the solution!
Take out the 3rd row light
Look at the back and locate an area where you can run a self taping screw through that will hit the bracket behind it but not hit the metal strips that carry the power
This may seem a little crazy but believe me I tried many things and this was the only thing that worked.
I just tried to upload two pictures to show where the screw goes but in will not let me. I will upload them when possible.
Just remember to use a self taper that isn't too long and make sure it has a large flat head so that it doesn't eventually pull through, also don't tighten it all the way down, just enough to where the headliner is snug.
Hopefully this is all clear, been writing this while I'm busy at work.
